[deliverable/linux.git] / tools / lib / api / fs / fs.c

#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/vfs.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mount.h>

#include "fs.h"
#include "debug-internal.h"

#define _STR(x) #x
#define STR(x) _STR(x)

#ifndef SYSFS_MAGIC
#define SYSFS_MAGIC            0x62656572
#endif

#ifndef PROC_SUPER_MAGIC
#define PROC_SUPER_MAGIC       0x9fa0
#endif

#ifndef DEBUGFS_MAGIC
#define DEBUGFS_MAGIC          0x64626720
#endif

#ifndef TRACEFS_MAGIC
#define TRACEFS_MAGIC          0x74726163
#endif

static const char * const sysfs__fs_known_mountpoints[] = {
	"/sys",
	0,
};

static const char * const procfs__known_mountpoints[] = {
	"/proc",
	0,
};

#ifndef DEBUGFS_DEFAULT_PATH
#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
#endif

static const char * const debugfs__known_mountpoints[] = {
	DEBUGFS_DEFAULT_PATH,
	"/debug",
	0,
};


#ifndef TRACEFS_DEFAULT_PATH
#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
#endif

static const char * const tracefs__known_mountpoints[] = {
	TRACEFS_DEFAULT_PATH,
	"/sys/kernel/debug/tracing",
	"/tracing",
	"/trace",
	0,
};

struct fs {
	const char		*name;
	const char * const	*mounts;
	char			 path[PATH_MAX];
	bool			 found;
	long			 magic;
};

enum {
	FS__SYSFS   = 0,
	FS__PROCFS  = 1,
	FS__DEBUGFS = 2,
	FS__TRACEFS = 3,
};

#ifndef TRACEFS_MAGIC
#define TRACEFS_MAGIC 0x74726163
#endif

static struct fs fs__entries[] = {
	[FS__SYSFS] = {
		.name	= "sysfs",
		.mounts	= sysfs__fs_known_mountpoints,
		.magic	= SYSFS_MAGIC,
	},
	[FS__PROCFS] = {
		.name	= "proc",
		.mounts	= procfs__known_mountpoints,
		.magic	= PROC_SUPER_MAGIC,
	},
	[FS__DEBUGFS] = {
		.name	= "debugfs",
		.mounts	= debugfs__known_mountpoints,
		.magic	= DEBUGFS_MAGIC,
	},
	[FS__TRACEFS] = {
		.name	= "tracefs",
		.mounts	= tracefs__known_mountpoints,
		.magic	= TRACEFS_MAGIC,
	},
};

static bool fs__read_mounts(struct fs *fs)
{
	bool found = false;
	char type[100];
	FILE *fp;

	fp = fopen("/proc/mounts", "r");
	if (fp == NULL)
		return NULL;

	while (!found &&
	       fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",
		      fs->path, type) == 2) {

		if (strcmp(type, fs->name) == 0)
			found = true;
	}

	fclose(fp);
	return fs->found = found;
}

static int fs__valid_mount(const char *fs, long magic)
{
	struct statfs st_fs;

	if (statfs(fs, &st_fs) < 0)
		return -ENOENT;
	else if ((long)st_fs.f_type != magic)
		return -ENOENT;

	return 0;
}

static bool fs__check_mounts(struct fs *fs)
{
	const char * const *ptr;

	ptr = fs->mounts;
	while (*ptr) {
		if (fs__valid_mount(*ptr, fs->magic) == 0) {
			fs->found = true;
			strcpy(fs->path, *ptr);
			return true;
		}
		ptr++;
	}

	return false;
}

static void mem_toupper(char *f, size_t len)
{
	while (len) {
		*f = toupper(*f);
		f++;
		len--;
	}
}

/*
 * Check for "NAME_PATH" environment variable to override fs location (for
 * testing). This matches the recommendation in Documentation/sysfs-rules.txt
 * for SYSFS_PATH.
 */
static bool fs__env_override(struct fs *fs)
{
	char *override_path;
	size_t name_len = strlen(fs->name);
	/* name + "_PATH" + '\0' */
	char upper_name[name_len + 5 + 1];
	memcpy(upper_name, fs->name, name_len);
	mem_toupper(upper_name, name_len);
	strcpy(&upper_name[name_len], "_PATH");

	override_path = getenv(upper_name);
	if (!override_path)
		return false;

	fs->found = true;
	strncpy(fs->path, override_path, sizeof(fs->path));
	return true;
}

static const char *fs__get_mountpoint(struct fs *fs)
{
	if (fs__env_override(fs))
		return fs->path;

	if (fs__check_mounts(fs))
		return fs->path;

	if (fs__read_mounts(fs))
		return fs->path;

	return NULL;
}

static const char *fs__mountpoint(int idx)
{
	struct fs *fs = &fs__entries[idx];

	if (fs->found)
		return (const char *)fs->path;

	return fs__get_mountpoint(fs);
}

static const char *mount_overload(struct fs *fs)
{
	size_t name_len = strlen(fs->name);
	/* "PERF_" + name + "_ENVIRONMENT" + '\0' */
	char upper_name[5 + name_len + 12 + 1];

	snprintf(upper_name, name_len, "PERF_%s_ENVIRONMENT", fs->name);
	mem_toupper(upper_name, name_len);

	return getenv(upper_name) ?: *fs->mounts;
}

static const char *fs__mount(int idx)
{
	struct fs *fs = &fs__entries[idx];
	const char *mountpoint;

	if (fs__mountpoint(idx))
		return (const char *)fs->path;

	mountpoint = mount_overload(fs);

	if (mount(NULL, mountpoint, fs->name, 0, NULL) < 0)
		return NULL;

	return fs__check_mounts(fs) ? fs->path : NULL;
}

#define FS(name, idx)				\
const char *name##__mountpoint(void)		\
{						\
	return fs__mountpoint(idx);		\
}						\
						\
const char *name##__mount(void)			\
{						\
	return fs__mount(idx);			\
}						\
						\
bool name##__configured(void)			\
{						\
	return name##__mountpoint() != NULL;	\
}

FS(sysfs,   FS__SYSFS);
FS(procfs,  FS__PROCFS);
FS(debugfs, FS__DEBUGFS);
FS(tracefs, FS__TRACEFS);

int filename__read_int(const char *filename, int *value)
{
	char line[64];
	int fd = open(filename, O_RDONLY), err = -1;

	if (fd < 0)
		return -1;

	if (read(fd, line, sizeof(line)) > 0) {
		*value = atoi(line);
		err = 0;
	}

	close(fd);
	return err;
}

/*
 * Parses @value out of @filename with strtoull.
 * By using 0 for base, the strtoull detects the
 * base automatically (see man strtoull).
 */
int filename__read_ull(const char *filename, unsigned long long *value)
{
	char line[64];
	int fd = open(filename, O_RDONLY), err = -1;

	if (fd < 0)
		return -1;

	if (read(fd, line, sizeof(line)) > 0) {
		*value = strtoull(line, NULL, 0);
		if (*value != ULLONG_MAX)
			err = 0;
	}

	close(fd);
	return err;
}

#define STRERR_BUFSIZE  128     /* For the buffer size of strerror_r */

int filename__read_str(const char *filename, char **buf, size_t *sizep)
{
	size_t size = 0, alloc_size = 0;
	void *bf = NULL, *nbf;
	int fd, n, err = 0;
	char sbuf[STRERR_BUFSIZE];

	fd = open(filename, O_RDONLY);
	if (fd < 0)
		return -errno;

	do {
		if (size == alloc_size) {
			alloc_size += BUFSIZ;
			nbf = realloc(bf, alloc_size);
			if (!nbf) {
				err = -ENOMEM;
				break;
			}

			bf = nbf;
		}

		n = read(fd, bf + size, alloc_size - size);
		if (n < 0) {
			if (size) {
				pr_warning("read failed %d: %s\n", errno,
					 strerror_r(errno, sbuf, sizeof(sbuf)));
				err = 0;
			} else
				err = -errno;

			break;
		}

		size += n;
	} while (n > 0);

	if (!err) {
		*sizep = size;
		*buf   = bf;
	} else
		free(bf);

	close(fd);
	return err;
}

int procfs__read_str(const char *entry, char **buf, size_t *sizep)
{
	char path[PATH_MAX];
	const char *procfs = procfs__mountpoint();

	if (!procfs)
		return -1;

	snprintf(path, sizeof(path), "%s/%s", procfs, entry);

	return filename__read_str(path, buf, sizep);
}

int sysfs__read_ull(const char *entry, unsigned long long *value)
{
	char path[PATH_MAX];
	const char *sysfs = sysfs__mountpoint();

	if (!sysfs)
		return -1;

	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);

	return filename__read_ull(path, value);
}

int sysfs__read_int(const char *entry, int *value)
{
	char path[PATH_MAX];
	const char *sysfs = sysfs__mountpoint();

	if (!sysfs)
		return -1;

	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);

	return filename__read_int(path, value);
}

int sysfs__read_str(const char *entry, char **buf, size_t *sizep)
{
	char path[PATH_MAX];
	const char *sysfs = sysfs__mountpoint();

	if (!sysfs)
		return -1;

	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);

	return filename__read_str(path, buf, sizep);
}

int sysctl__read_int(const char *sysctl, int *value)
{
	char path[PATH_MAX];
	const char *procfs = procfs__mountpoint();

	if (!procfs)
		return -1;

	snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl);

	return filename__read_int(path, value);
}
Commit	Line	Data
f2d9627b	1	#include <ctype.h>
cd0cfad7	2	#include <errno.h>
2d729f6a	3	#include <limits.h>
cd0cfad7 BP	4	#include <stdbool.h>
cd0cfad7 BP	5	#include <stdio.h>
f2d9627b	6	#include <stdlib.h>
cd0cfad7 BP	7	#include <string.h>
cd0cfad7 BP	8	#include <sys/vfs.h>
3a351127 ACM	9	#include <sys/types.h>
	10	#include <sys/stat.h>
	11	#include <fcntl.h>
	12	#include <unistd.h>
73ca85ad	13	#include <sys/mount.h>
4299a549	14
cd0cfad7	15	#include "fs.h"
607bfbd7	16	#include "debug-internal.h"
4299a549	17
b86b0d35 JO	18	#define _STR(x) #x
	19	#define STR(x) _STR(x)
	20
41e3a1fe JO	21	#ifndef SYSFS_MAGIC
	22	#define SYSFS_MAGIC 0x62656572
	23	#endif
	24
	25	#ifndef PROC_SUPER_MAGIC
	26	#define PROC_SUPER_MAGIC 0x9fa0
	27	#endif
	28
8ccfabdb JO	29	#ifndef DEBUGFS_MAGIC
	30	#define DEBUGFS_MAGIC 0x64626720
	31	#endif
	32
c495afb4 JO	33	#ifndef TRACEFS_MAGIC
	34	#define TRACEFS_MAGIC 0x74726163
	35	#endif
	36
4299a549 JO	37	static const char * const sysfs__fs_known_mountpoints[] = {
	38	"/sys",
	39	0,
	40	};
	41
a9862418 JO	42	static const char * const procfs__known_mountpoints[] = {
	43	"/proc",
	44	0,
	45	};
	46
8ccfabdb JO	47	#ifndef DEBUGFS_DEFAULT_PATH
	48	#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
	49	#endif
	50
	51	static const char * const debugfs__known_mountpoints[] = {
	52	DEBUGFS_DEFAULT_PATH,
	53	"/debug",
	54	0,
	55	};
	56
c495afb4 JO	57
	58	#ifndef TRACEFS_DEFAULT_PATH
	59	#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
	60	#endif
	61
	62	static const char * const tracefs__known_mountpoints[] = {
	63	TRACEFS_DEFAULT_PATH,
	64	"/sys/kernel/debug/tracing",
	65	"/tracing",
	66	"/trace",
	67	0,
	68	};
	69
4299a549 JO	70	struct fs {
	71	const char *name;
	72	const char * const *mounts;
ccb5597f	73	char path[PATH_MAX];
4299a549 JO	74	bool found;
	75	long magic;
	76	};
	77
	78	enum {
8ccfabdb JO	79	FS__SYSFS = 0,
	80	FS__PROCFS = 1,
	81	FS__DEBUGFS = 2,
c495afb4	82	FS__TRACEFS = 3,
4299a549 JO	83	};
4299a549 JO	84
c495afb4 JO	85	#ifndef TRACEFS_MAGIC
	86	#define TRACEFS_MAGIC 0x74726163
	87	#endif
	88
4299a549 JO	89	static struct fs fs__entries[] = {
	90	[FS__SYSFS] = {
	91	.name = "sysfs",
	92	.mounts = sysfs__fs_known_mountpoints,
	93	.magic = SYSFS_MAGIC,
	94	},
a9862418 JO	95	[FS__PROCFS] = {
	96	.name = "proc",
	97	.mounts = procfs__known_mountpoints,
	98	.magic = PROC_SUPER_MAGIC,
	99	},
8ccfabdb JO	100	[FS__DEBUGFS] = {
	101	.name = "debugfs",
	102	.mounts = debugfs__known_mountpoints,
	103	.magic = DEBUGFS_MAGIC,
	104	},
c495afb4 JO	105	[FS__TRACEFS] = {
	106	.name = "tracefs",
	107	.mounts = tracefs__known_mountpoints,
	108	.magic = TRACEFS_MAGIC,
	109	},
4299a549 JO	110	};
	111
	112	static bool fs__read_mounts(struct fs *fs)
	113	{
	114	bool found = false;
	115	char type[100];
	116	FILE *fp;
	117
	118	fp = fopen("/proc/mounts", "r");
	119	if (fp == NULL)
	120	return NULL;
	121
	122	while (!found &&
	123	fscanf(fp, "%s %" STR(PATH_MAX) "s %99s %s %d %d\n",
	124	fs->path, type) == 2) {
	125
	126	if (strcmp(type, fs->name) == 0)
	127	found = true;
	128	}
	129
	130	fclose(fp);
	131	return fs->found = found;
	132	}
	133
	134	static int fs__valid_mount(const char *fs, long magic)
	135	{
	136	struct statfs st_fs;
	137
	138	if (statfs(fs, &st_fs) < 0)
	139	return -ENOENT;
db1806ed	140	else if ((long)st_fs.f_type != magic)
4299a549 JO	141	return -ENOENT;
	142
	143	return 0;
	144	}
	145
	146	static bool fs__check_mounts(struct fs *fs)
	147	{
	148	const char * const *ptr;
	149
	150	ptr = fs->mounts;
	151	while (*ptr) {
	152	if (fs__valid_mount(*ptr, fs->magic) == 0) {
	153	fs->found = true;
	154	strcpy(fs->path, *ptr);
	155	return true;
	156	}
	157	ptr++;
	158	}
	159
	160	return false;
	161	}
	162
f2d9627b CS	163	static void mem_toupper(char *f, size_t len)
	164	{
	165	while (len) {
	166	f = toupper(f);
	167	f++;
	168	len--;
	169	}
	170	}
	171
	172	/*
	173	* Check for "NAME_PATH" environment variable to override fs location (for
	174	* testing). This matches the recommendation in Documentation/sysfs-rules.txt
	175	* for SYSFS_PATH.
	176	*/
	177	static bool fs__env_override(struct fs *fs)
	178	{
	179	char *override_path;
	180	size_t name_len = strlen(fs->name);
	181	/* name + "_PATH" + '\0' */
	182	char upper_name[name_len + 5 + 1];
	183	memcpy(upper_name, fs->name, name_len);
	184	mem_toupper(upper_name, name_len);
	185	strcpy(&upper_name[name_len], "_PATH");
	186
	187	override_path = getenv(upper_name);
	188	if (!override_path)
	189	return false;
	190
	191	fs->found = true;
	192	strncpy(fs->path, override_path, sizeof(fs->path));
	193	return true;
	194	}
	195
4299a549 JO	196	static const char fs__get_mountpoint(struct fs fs)
4299a549 JO	197	{
f2d9627b CS	198	if (fs__env_override(fs))
	199	return fs->path;
	200
4299a549 JO	201	if (fs__check_mounts(fs))
	202	return fs->path;
	203
f2d9627b CS	204	if (fs__read_mounts(fs))
	205	return fs->path;
	206
	207	return NULL;
4299a549 JO	208	}
4299a549 JO	209
cf38fada	210	static const char *fs__mountpoint(int idx)
4299a549 JO	211	{
	212	struct fs *fs = &fs__entries[idx];
	213
	214	if (fs->found)
	215	return (const char *)fs->path;
	216
	217	return fs__get_mountpoint(fs);
	218	}
	219
73ca85ad JO	220	static const char mount_overload(struct fs fs)
	221	{
	222	size_t name_len = strlen(fs->name);
	223	/* "PERF_" + name + "_ENVIRONMENT" + '\0' */
	224	char upper_name[5 + name_len + 12 + 1];
	225
	226	snprintf(upper_name, name_len, "PERF_%s_ENVIRONMENT", fs->name);
	227	mem_toupper(upper_name, name_len);
	228
	229	return getenv(upper_name) ?: *fs->mounts;
	230	}
	231
	232	static const char *fs__mount(int idx)
	233	{
	234	struct fs *fs = &fs__entries[idx];
	235	const char *mountpoint;
	236
	237	if (fs__mountpoint(idx))
	238	return (const char *)fs->path;
	239
	240	mountpoint = mount_overload(fs);
	241
	242	if (mount(NULL, mountpoint, fs->name, 0, NULL) < 0)
	243	return NULL;
	244
	245	return fs__check_mounts(fs) ? fs->path : NULL;
	246	}
	247
709adcb3 JO	248	#define FS(name, idx) \
	249	const char *name##__mountpoint(void) \
	250	{ \
	251	return fs__mountpoint(idx); \
	252	} \
	253	\
	254	const char *name##__mount(void) \
	255	{ \
	256	return fs__mount(idx); \
	257	} \
	258	\
	259	bool name##__configured(void) \
	260	{ \
	261	return name##__mountpoint() != NULL; \
4299a549 JO	262	}
4299a549 JO	263
73ca85ad JO	264	FS(sysfs, FS__SYSFS);
	265	FS(procfs, FS__PROCFS);
	266	FS(debugfs, FS__DEBUGFS);
	267	FS(tracefs, FS__TRACEFS);
3a351127 ACM	268
	269	int filename__read_int(const char filename, int value)
	270	{
	271	char line[64];
	272	int fd = open(filename, O_RDONLY), err = -1;
	273
	274	if (fd < 0)
	275	return -1;
	276
	277	if (read(fd, line, sizeof(line)) > 0) {
	278	*value = atoi(line);
	279	err = 0;
	280	}
	281
	282	close(fd);
	283	return err;
	284	}
42e3c4a1	285
db49120a JO	286	/*
	287	* Parses @value out of @filename with strtoull.
	288	* By using 0 for base, the strtoull detects the
	289	* base automatically (see man strtoull).
	290	*/
2d729f6a ACM	291	int filename__read_ull(const char filename, unsigned long long value)
	292	{
	293	char line[64];
	294	int fd = open(filename, O_RDONLY), err = -1;
	295
	296	if (fd < 0)
	297	return -1;
	298
	299	if (read(fd, line, sizeof(line)) > 0) {
db49120a	300	*value = strtoull(line, NULL, 0);
2d729f6a ACM	301	if (*value != ULLONG_MAX)
	302	err = 0;
	303	}
	304
	305	close(fd);
	306	return err;
	307	}
	308
607bfbd7 JO	309	#define STRERR_BUFSIZE 128 /* For the buffer size of strerror_r */
	310
	311	int filename__read_str(const char filename, char buf, size_t sizep)
	312	{
	313	size_t size = 0, alloc_size = 0;
	314	void bf = NULL, nbf;
	315	int fd, n, err = 0;
	316	char sbuf[STRERR_BUFSIZE];
	317
	318	fd = open(filename, O_RDONLY);
	319	if (fd < 0)
	320	return -errno;
	321
	322	do {
	323	if (size == alloc_size) {
	324	alloc_size += BUFSIZ;
	325	nbf = realloc(bf, alloc_size);
	326	if (!nbf) {
	327	err = -ENOMEM;
	328	break;
	329	}
	330
	331	bf = nbf;
	332	}
	333
	334	n = read(fd, bf + size, alloc_size - size);
	335	if (n < 0) {
	336	if (size) {
	337	pr_warning("read failed %d: %s\n", errno,
	338	strerror_r(errno, sbuf, sizeof(sbuf)));
	339	err = 0;
	340	} else
	341	err = -errno;
	342
	343	break;
	344	}
	345
	346	size += n;
	347	} while (n > 0);
	348
	349	if (!err) {
	350	*sizep = size;
	351	*buf = bf;
	352	} else
	353	free(bf);
	354
	355	close(fd);
	356	return err;
	357	}
4bd112df ACM	358
	359	int procfs__read_str(const char entry, char buf, size_t sizep)
	360	{
	361	char path[PATH_MAX];
	362	const char *procfs = procfs__mountpoint();
	363
	364	if (!procfs)
	365	return -1;
	366
	367	snprintf(path, sizeof(path), "%s/%s", procfs, entry);
	368
	369	return filename__read_str(path, buf, sizep);
	370	}
607bfbd7	371
2d729f6a ACM	372	int sysfs__read_ull(const char entry, unsigned long long value)
	373	{
	374	char path[PATH_MAX];
	375	const char *sysfs = sysfs__mountpoint();
	376
	377	if (!sysfs)
	378	return -1;
	379
	380	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
	381
	382	return filename__read_ull(path, value);
	383	}
	384
	385	int sysfs__read_int(const char entry, int value)
	386	{
	387	char path[PATH_MAX];
	388	const char *sysfs = sysfs__mountpoint();
	389
	390	if (!sysfs)
	391	return -1;
	392
	393	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
	394
	395	return filename__read_int(path, value);
	396	}
	397
51c0396c JO	398	int sysfs__read_str(const char entry, char buf, size_t sizep)
	399	{
	400	char path[PATH_MAX];
	401	const char *sysfs = sysfs__mountpoint();
	402
	403	if (!sysfs)
	404	return -1;
	405
	406	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
	407
	408	return filename__read_str(path, buf, sizep);
	409	}
	410
42e3c4a1 ACM	411	int sysctl__read_int(const char sysctl, int value)
	412	{
	413	char path[PATH_MAX];
	414	const char *procfs = procfs__mountpoint();
	415
	416	if (!procfs)
	417	return -1;
	418
	419	snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl);
	420
	421	return filename__read_int(path, value);
	422	}